hey guy i was tig welding some sheet metal today using 3/32 2 % lanthenated, 55 amps,dc,er 70s-2. welds were turning out pretty good but my tungsten would stay sharp for long? pretty much i could lay 2 beads and then i would have to re sharpen it. it also kinda of turning a bit black but not so much. other info i can say i was using a gas lens and cup # 7 10 cfh which i was told was plenty if using a gas lense. i was simply just running beads. any one have any suggestions on why the tungsten wouldnt stay sharp and deteriating a bit.?????????????????